The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of tiling, are neither expressly or impliedly admitted as prior art against the present invention.
Passive keyless systems afford greater user convenience since they can open a vehicle door or start an ignition all while a key fob can remain in a user's pocket, backpack, purse, etc. as long as it is within range of the vehicle. Passive keyless systems can include passive keyless entry and start (PKES), passive keyless entry (PKE) without passive start, and passive keyless start (PKS) without passive entry. Moreover, physical lock and key systems are prone to security breaches via copied keys or picked locks, which a keyless entry can prevent. A system that actively protects against possible security breaches to this new keyless system, known as “relay attacks”, is needed.